<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		圆的半径：<input type="text"id="input1"/>
		<button onclick="calc()">计算</button>
		<script>
			console.log("π="+math.PI);
			function calc()
			{
				var r=parseFloat(input1.value)
				var area=math.PI*r*;
				alert("圆的面积："+area);
				console.log(math.abs(-10));
				console.log(math.round(4.4));
				console.log(math.floor(4.5));
				console.log(math.pow(2,10));
				console.log(math.sqrt(16));
				console.log(math.floor(math.random()*10+1));
				console.log(math.floor(math.random()*3+1));
				
			}
		</script>
	</body>
</html>
